Research On Friction-reduction And Lifetime Extension Of Lightweight Self-lubricating Bearing Based On Laser Surface Texturing

Self-lubricating spherical plain bearing are widely used in aviation,aerospace,military industry,transportation and other fields due to their advantages of good selflubrication,high load,self-aligning and strong impact resistance,which is developing towards lightweight and high-end.With the rapid development of industrial technology,higher requirements are put forward for the manufacturing industry.Due to the heavy weight of the traditional spherical plain bearing,and the liner is easy to wear and fall off in the use process,resulting in greatly limited application in the high-end field.In this paper,TC11 titanium alloy was used as the base material and DLC/TiAlN coating was coated on the surface to improve the friction and wear performance of the spherical plain bearing.Aim at the problem that the liner is easy to fall off and fail to realize selflubrication in the process of long-term friction of the spherical plain bearing,it is proposed to carry out laser texturing treatment on the surface of the substrate,by increasing the specific surface area of the adhesive layer and the substrate,enhancing the mechanical bite force,etc.,the bonding quality between the liner and the substrate is enhanced,and to extend its service life.First of all,the texture of TC11 substrate was treated by using an acousto-optic Qswitched diode pumped Nd:YAG solid-state laser,by changing the single pulse energy,pulse repetition times,defocusing amount and other process parameters,the influence of the laser on the texture was researched.Secondly,ABAQUS software was used to simulate the bonding strength of the interface between the textured matrix surface and the adhesive layer,focusing on the influence of texture morphology,texture density,taper angle,adhesive layer thickness and other factors on the bonding force.The results of the numerical simulation were verified by the hot and humid adhesion stripping test.Finally,the friction test was carried out on the Rtec-instrument universal friction and wear tester with the samples bonded with PTFE film on the lower surface of the upper sample and coated with DLC/TiAlN coating on the surface of the lower sample.The effects of different surface treatment,texture density and working condition parameters on the tribological properties were researched.Through the self-lubricating spherical plain bearing test bench,the wear form and wear mechanism were explored.The conclusion of this research are as follows:(1)When the single pulse energy and pulse repetition times of laser are changed,the micro-dimple diameter and depth increase linearly first and then slowly with the increase of single pulse energy and repetition times;when the defocusing amount is changed,the micro-dimple diameter and depth obtain the maximum value at the focus.(2)Texture treatment on the surface of the substrate can effectively enhance the interface bonding force.When the V-shape is machined on the surface of the substrate,the maximum peel force increases about 13%,and with the increase of the V-shape taper angle,the interface bonding force decreases gradually;With the increase of the texture density,the interface bonding force increases gradually,when the texture density is 34.7%,the maximum peel force increases about 17.4%;When the thickness of adhesive layer is different on the surface of the matrix,the bonding force of the interface decreases slowly at first and then increases,properly increasing the thickness of adhesive layer can effectively enhance the bonding strength,which increases by about 23.9%.When the thickness of adhesive layer exceeds 0.3mm,the change of the bonding strength is not obvious,only 4.4%.(3)The results of peel test showed that the interface bonding strength increases with the increase of texture density and diameter,which is consistent with the trend of numerical simulation,it further shows that the texture treatment on the surface of the matrix can effectively enhance the interface bonding strength.(4)Through the integration and fusion of laser texturing technology,solid-grease composite lubrication technology and coating technology,the tribological properties of TiAlN coating surface are greatly improved.When the texture density is changed,the friction coefficient decreases first and then increases.For the surface coated with DLC,when the texture density is 30%,the friction coefficient is the lowest,only 0.079.For the surface coated with TiAlN,when the texture density is 40%,the friction coefficient is the lowest,only 0.068;With the increase of load,the friction coefficient tends to decrease gradually;With the increase of rotational speed,the friction coefficient increases slightly at first and then decreases.(5)The main wear forms of self-lubricating spherical plain bearing are abrasive wear and oxidation wear.The micro-texture and self-lubricating treatment on the inner outer sphere of spherical plain bearing can effectively improve the lubrication characteristics of spherical plain bearing.